KR20120110245A - A method for preparing vinyl chloride-based polymers having improved workability - Google Patents

Abstract

PURPOSE: A manufacturing method of a vinyl chloride polymer is provided to obtain vinyl chloride polymer with improved quality performance of fish eye and apparent viscosity, and to prevent attachment of scale to inside of a reactor and to increase heat-removing effect of a reflux condenser by remarkably removing bubbles generated during a reaction. CONSTITUTION: A manufacturing method of a vinyl chloride polymer comprises a step of polymerizing vinyl chloride monomers through suspension polymerization while putting a dispersant into. The suspension polymerization is polymerized by putting high-temperature polymerization water of 70-100 °C into a rector. The dispersant is polyvinylalcohol of which degree of hydration is 86-92 %. An additional input of the polyvinyl alcohol is 0.005-0.050 parts by weight based on 100.0 parts by weight of the vinyl chloride monomer put in before initiating the polymerization.

Description

A method for preparing vinyl chloride? Based polymers having improved workability

The present invention relates to a method for producing a vinyl chloride polymer with improved processability, and more particularly, to a method for preparing a vinyl chloride polymer by suspension polymerization of a vinyl chloride monomer, to suppress the formation of bubbles generated by adding a dispersant to a reflux condenser. The present invention provides a method for suspending polymerization of vinyl chloride polymer having improved fisciyi and particle size distribution by improving the heat removal capacity of the product and improving productivity by shortening the polymerization time and suppressing generation of scale in the reactor. In addition, it is to provide a suspension polymerization method that can improve the apparent specific gravity, which is a very important physical property during vinyl chloride processing.

The vinyl chloride polymer refers to a hybrid polymer obtained by polymerizing a mixture of vinyl chloride or a monomer copolymerizable with vinyl chloride.

In general, vinyl chloride polymer has been used in various fields because of its low cost, easy processing and simple polymerization process. In addition, it is possible to prepare a polymer having a different degree of polymerization by simply controlling the polymerization temperature, and because it has different properties depending on the degree of polymerization, it is possible to apply to two fields of hard and soft.

First, in the hard field, it is used for pipes, films, window frames, and the like, and in the soft field, it is used for wire coating, wrap films, sheets, and the like.

In addition, the polymerization method of the vinyl chloride polymer is mainly prepared by emulsion polymerization method and suspension polymerization method, in the suspension polymerization method is suspended using water, suspension stabilizer, vinyl chloride monomer, initiator, and polymerized into particles of about 150 ㎛ Processing is possible immediately after drying. The vinyl chloride polymer thus polymerized has excellent electrical insulation properties and excellent chemical resistance, and thus is widely used as a chemical container.

In the case of emulsion polymerization, polymerization is carried out using water, an emulsifier, a vinyl chloride monomer, and an initiator. In the case of emulsion polymerization, a vinyl chloride monomer prepared by emulsion polymerization has excellent viscosity stability and has good flowability when processing a product. It is excellent in foaming and used as flooring material.

Suspension polymerization of the vinyl chloride monomer is usually carried out in a batch manner, and after adding the vinyl chloride monomer and the initiator additive, water vapor is added to the jacket of the polymerization reactor to circulate warm water to start the polymerization reaction. When the heat is generated by the exothermic reaction, the vinyl chloride polymer is polymerized by flowing cooling water through the jacket to maintain the polymerization temperature. An example is Korea Patent Publication No. 2010-005281.

However, the polymerization in this conventional manner causes bubbles formed during the reaction to rise to the reflux condenser to contaminate the inside of the condenser, and these contaminants act as whiskey during processing. In addition, the bubbles generated at this time are generated on the scale in the polymerization reactor to reduce the PVC properties and lower the heat removal efficiency of the reflux condenser to reduce the conversion rate, it is difficult to wash the reactor may cause a decrease in production.

Therefore, in order to solve this problem, various methods have been proposed. In the case of vinyl chloride polymer polymerization, a method for preparing a vinyl chloride monomer that polymerizes by adding an antifoaming agent at a time of 10% or less of the heat of the reflux condenser is polymerized is Japan. It is disclosed in Japanese Patent Laid-Open No. 2-180908.

In addition, Japanese Unexamined Patent Application Publication No. 7-286003 and the like have proposed a method for producing a vinyl chloride polymer in which an acetylene glycol derivative having a specific structure is added as an antifoaming agent during suspension polymerization. However, although the addition of the antifoaming agent has an effect of suppressing the foam of the reaction system, there is a disadvantage that the antifoaming agent affects the particle formation of the polymer and adversely affects the physical properties.

In order to solve the problems of the prior art as described above, the present inventors can suppress the generation of bubbles to improve the descaling effect and the heat removal effect of the reflux condenser, while obtaining a vinyl chloride polymer having improved whiskey for soft extrusion. In the case of hard extrusion, while continuing to study how to improve the apparent specific gravity characteristics, adding a dispersant at a certain time to a specific content, while suppressing the foaming, the processability is improved to solve the above problems and stable quality It was confirmed that it could be ensured and came to complete this invention.

That is, an object of the present invention is to prepare a vinyl chloride polymer by suspension polymerization of a vinyl chloride monomer, a specific dispersant at a polymerization conversion rate of 30 to 60% when the foaming occurs a lot during suspension polymerization in a reactor equipped with a reflux condenser The present invention aims to provide a suspension polymerization method of vinyl chloride polymer which can reduce the adhesion of scale to the reactor by adding bubbles, thereby improving the whiskey characteristics, increasing the apparent specific gravity, improving the particle size distribution, and providing high productivity. .

In the present invention, in the method for producing a vinyl chloride polymer by suspension polymerization, the suspension polymerization is characterized in that the polymerization by adding a dispersant.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

In the present invention, the vinyl chloride monomer is polymerized, but the polymerization is started in the presence of a suspension stabilizer, a polymerization initiator, and a vinyl chloride monomer, and the dispersant is continuously or intermittently added at a polymerization conversion rate of 30 to 60%, which is a point where foaming occurs a lot during polymerization. It has the technical feature to efficiently reduce the foam generated by the addition.

In this case, the point of addition of the dispersant is limited to the point of polymerization conversion rate of 30 to 60%. If the dispersant is added before the reaction or at the beginning of the reaction, it affects the stability of the overall polymerization reaction and thus the particle, plasticizer absorption rate, and content of the fine particles. It is desirable to add at least 30% after the polymerization conversion rate because it affects the overall physical properties.

In addition, if the dispersant is added after 60% of the polymerization conversion rate, since the reaction is already performed in a considerable amount, since the scale is generated in the reactor or the reflux condenser by the generated bubbles, it is not preferable because it is not effective in suppressing the scale.

Meanwhile, the dispersant added at this time is not limited thereto, but polyvinyl alcohol having a water solubility of 86 to 92% is preferably used. When the water solubility is lower than this, the solubility in water is high and the viscosity is high. Not only is it difficult to handle, it also has the disadvantage of causing coagulation between particles or lowering the apparent specific gravity. In addition, the use of dispersants having a degree of hydration of 92% or more is not suitable for use in terms of price.

The amount added as these dispersants is preferably in the range of 0.005 to 0.050 parts by weight based on 100 parts by weight of the initially introduced vinyl chloride monomer, if the content exceeds this has an undesirable effect on the physical properties, if a small amount is added The ability to inhibit foam is lowered, which is undesirable in terms of whiskey or descaling.

In the suspension polymerization, 100 parts by weight of a vinyl chloride monomer is added, and then 100 to 120 parts by weight of high-temperature polymerization water at 70 to 100 ° C. starts the polymerization reaction, thereby providing economic efficiency according to the heat-up free effect. The effect can be maximized. In this case, when the polymerization water of less than 70 ℃ is used, when the vinyl chloride polymer is manufactured, the polymerization reaction cannot be started immediately, and heating is required until the target polymerization temperature is reached.

Specifically, in the suspension polymerization, the vinyl chloride monomer and the protective colloid preparation are mixed with the high temperature polymerization water, and a polymerization initiator is added to the mixed solution to polymerize.

For reference, the vinyl chloride polymer of the present invention is a mixture of a vinyl chloride monomer composed mainly of a vinyl chloride monomer as well as a resin composed of a vinyl chloride monomer purely and copolymerizable with the vinyl chloride monomer content (more than 50% by weight of the vinyl chloride monomer in the total resin composition). Also includes.

Vinyl monomers copolymerizable with such vinyl chloride monomers include olefin compounds such as ethylene and propylene, vinyl esters such as vinyl acetate and vinyl propionate, unsaturated nitriles such as acrylonitrile, vinyl methyl ether and vinyl ethyl ether. In general, unsaturated monomers such as vinyl alkyl ethers, acrylic acid, methacrylic acid, itaconic acid, maleic acid, and anhydrides of these fatty acids, and monomers copolymerizable with vinyl chloride monomers can be used alone or in combination of two or more thereof.

In addition, the protective colloid preparation used for the purpose of maintaining a stable production process of the vinyl chloride polymer in the present invention to obtain a stable particle, the degree of hydration is 30 to 90% by weight and the viscosity of 4% aqueous solution at room temperature of 5 to 100 cps Phosphorus vinyl alcohol-based resin, 15% to 40% by weight of methoxy group, 3 to 20% by weight of propyl hydroxide group, and 1% selected from the group consisting of cellulose and unsaturated organic acid having a viscosity of 10 to 20,000 cps in a 2% aqueous solution measured at room temperature It is preferable to use the above within the range of 0.03 to 5 parts by weight, and more preferably 0.05 to 2.5 parts by weight based on 100 parts by weight of the initially introduced vinyl chloride monomer. This is because when the protective colloid preparation is less than 0.03 parts by weight, the droplet stability is lowered, and when it is more than 5 parts by weight, the whiskey properties are markedly degraded by the formation of beads. Since no particles are formed and no whiskey is generated, there is no increase in microparticles, so that the initial coloring property is excellent.

As the protective colloid preparation, 0.03 to 0.06 parts by weight of vinyl alcohol resin (high hydration resin) having a degree of hydration of 85 to 98%, and 0.01 to 0.03 parts of vinyl alcohol resin (medium hydration resin) having a degree of hydration of 62 to 82%. Most preferably, it is 0.06 parts by weight, 0.01 to 0.03 parts by weight of a vinyl alcohol resin (low degree of hydration resin) having a degree of hydration of 50 to 60%, and 0.005 to 0.02 parts by weight of a cellulose suspension stabilizer.

At this time, the mixing ratio of the high and medium water resin, the low water resin and the low water resin is adjusted according to the target physical properties, in the present invention, the high water resin, the medium water resin and the low water resin within the above-mentioned range. It is especially preferable to mix and use all.

In this case, specific examples of the unsaturated organic acid may be an acrylic acid polymer, methacrylic acid polymer, itaconic acid polymer, fumaric acid polymer, maleic acid polymer, succinic acid polymer, or gelatin.

Furthermore, as the polymerization initiator usable in the present invention, diacyl peroxides such as dicumyl peroxide, dipentyl peroxide, di-3,5,5-trimethyl hexanoyl peroxide, dilauroyl peroxide, and diisopropyl Peroxydicarbonates such as peroxydicarbonate, di-sec-butylperoxydicarbonate, di-2-ethylhexyl peroxydicarbonate, t-butylperoxy neodecanoate, t-butylperoxy neoheptanoate, t Peroxy esters such as amyl peroxy neodecanoate, cumyl peroxy neodecanoate, cumyl peroxy neoheptanoate, 1,1,3,3-tetramethylbutyl peroxy neodecanoate and azobis Azo compounds such as -2,4-dimethylvaleronitrile, sulfates such as potassium persulfate and ammonium persulfate, and the like, and these may be used alone or in combination of two or more thereof.

The amount of use is determined by factors such as manufacturing process, productivity and quality. Generally, the total amount of initiator can be used in an amount of 0.02 to 0.2 parts by weight based on 100 parts by weight of the initial vinyl chloride monomer before the start of polymerization. The use of 0.04-0.12 parts by weight is preferred. When the amount of the initiator is less than the proper amount, the reaction time is delayed and the productivity is lowered. When the amount of the initiator is used more than the proper amount, the initiator is not completely consumed during the polymerization process and remains in the final resin product to degrade the thermal stability and color quality of the resin.

The antioxidant which can be used prior to stopping the reaction in the present invention is sufficient to use the kind used in the preparation of the vinyl chloride polymer, for example triethylene glycol-bis- [3- (3-t-butyl -5-methyl-4-hydroxy phenyl) propionate, hydroquinone, p-methoxy phenol, t-butylhydroxyanisole, n-octadecyl-3- (4-hydroxy-3,5-di -t-butyl phenyl) propionate, 2,5-di-t-butyl hydroquinone, 4,4-butylidenebis (3-methyl-6-t-butyl phenol), t-butyl catechol, 4 Phenolic compounds such as, 4-thiobis (6-t-butyl-m-cresol), tocopherol, N, N-diphenyl-p-phenylene diamine and 4,4-bis (dimethylbenzyl) diphenylamine Sulfur compounds such as amine compounds, dodecyl mercaptan, 1,2-diphenyl-2-thiol, triphenyl phosphite, diphenyldecyl phosphite, phenylisodecyl phosphite, tri (nonylphenyl) phosphite and trira Us tree A phosphoric acid-based antioxidants such as Va'a-o seupayiteu may be mixed alone or in combination.

Suspension polymerization in the present invention, as defined in the following examples, to the 100 parts by weight of the initial vinyl chloride monomer before the start of the polymerization, 0.03 to 5 parts by weight of the protective colloid preparation and 0.02 to 0.2 parts by weight of the polymerization initiator, followed by vacuum degassing Then, 100 parts by weight of the vinyl chloride monomer and 100 to 120 parts by weight of the high temperature polymerization water were added to initiate suspension polymerization, and then 0.005 to 0.050 parts by weight of polyvinyl alcohol having a degree of hydration of 86-92% was continued at a polymerization conversion rate of 30 to 60%. Alternatively, by intermittently adding, it is possible to shorten the polymerization time and improve the particle size distribution while improving both the apparent specific gravity for the hard extrusion and the whiskey for the soft extrusion.

In the present invention, a polymerization regulator, a chain transfer agent, a pH regulator, an antioxidant, a crosslinking agent, an antistatic agent, an antiscaling agent, a surfactant, and the like may be added to the polymerization system before or after the start of polymerization, if necessary, and partially during the polymerization. May be added separately or continuously. The average degree of polymerization of the vinyl chloride polymer targeted by the present invention may be in the range of 500 to 3000.

Meanwhile, as the reactor used in the present invention, it is sufficient to use a stirring device which is generally used for suspension polymerization of vinyl chloride polymer. As a specific example, the stirring blade type is a paddle type and a pitch paddle. Agitators can be used alone or in combination with bloomers gin type, pfaudler type, turbine type and propeller type or combined with two or more stirring blades. , Cylindrical, D-shaped, looped or finger-type may be used.

The vinyl chloride polymer slurry prepared above may remove moisture with a fluidized bed dryer under ordinary reaction conditions and prepare a final vinyl chloride polymer.

According to the suspension polymerization method of the vinyl chloride polymer of the present invention, while obtaining a vinyl chloride polymer having improved quality characteristics of whiskey and apparent specific gravity, bubbles generated during the reaction are greatly removed to increase the heat removal effect of the reflux condenser and increase the It is possible to provide a suspension polymerization method of a vinyl chloride polymer in which scale adhesion is prevented to improve quality and productivity.

Hereinafter, preferred examples are provided to help understanding of the present invention, but the following examples are merely to illustrate the present invention, and the scope of the present invention is not limited to the following examples.

Example  One

Reflux condenser and a stirrer, the inside volume of 1 0.05 Polyvinyl alcohol is also a 88% hydrated groups stainless polymerization of m ³ attached to parts by weight, moisture content of 72% of polyvinyl alcohol 0.02 parts by weight of a moisture content of 55% of polyvinyl 0.015 parts by weight of alcohol, 0.01 parts by weight of hydroxypropylmethyl cellulose, 0.080 parts by weight of t-butylperoxy neodecanoate (BND) were added, followed by degassing the interior with a vacuum pump while stirring under 200 rpm.

Then, 300 kg (100 parts by weight) of vinyl chloride monomer was added thereto, and 360 kg (120 parts by weight) of polymerization water at 80 ° C. was added thereto.

The polymerization was carried out while maintaining the polymerization temperature at a polymerization reference temperature of 58 ° C. to achieve a target average polymerization degree of 1000 during the entire reaction process, and when the polymerization conversion rate was progressed from 30% to 60%, the polyhydric acid was 88%. 0.015 parts by weight of vinyl alcohol was continuously added.

The polymerization was stopped when the polymerization reactor pressure reached 1.0 kg / cm ² (the polymerization conversion rate was approximately 80 to 85%), and triethylene glycol-bis- [3- (3-t- as an antioxidant Butyl-5-methyl-4-hydroxy phenyl) propionate] was added thereto, and then the unreacted monomer was recovered and the resin slurry was recovered in a polymerization reactor. The slurry thus obtained was dried in a fluidized bed dryer in a conventional manner to obtain a vinyl chloride polymer.

Example  2

Except that the polyvinyl alcohol having a degree of hydration of 88% was continuously added at the time when the polymerization conversion rate was 30 to 60% after the polymerization was started in Example 1, by dividing 0.0075 parts by weight at 30% and 45%. The polymerization was carried out and evaluated under the same conditions as in Example 1.

Example  3

In Example 1, 0.05 parts by weight of polyvinyl alcohol having a degree of hydration of 88%, 0.02 parts by weight of polyvinyl alcohol having a degree of hydration of 72%, 0.015 part by weight of polyvinyl alcohol having a degree of hydration of 55%, hydroxypropylmethyl cellulose 0.01 0.04 parts by weight of polyvinyl alcohol having a degree of hydration of 88%, 0.45 parts by weight of polyvinyl alcohol having a degree of hydration of 72%, 0.017 parts by weight of polyvinyl alcohol having a degree of hydration of 55%, and hydroxypropylmethyl cellulose The polymerization was carried out and evaluated under the same conditions as in Example 1, except that 0.005 parts by weight of the protective colloid preparation was added.

Example  4

The polymerization was carried out under the same conditions as in Example 1, except that 0.015 parts by weight of the 88% polyvinyl alcohol was added as 0.005 parts by weight as a dispersant to be added when the polymerization conversion rate was in the range of 30 to 60% in Example 1. And evaluated.

Example  5

In Example 1, the polymerization temperature was changed to 52 ° C., 0.05 parts by weight of polyvinyl alcohol having a degree of hydration of 88%, 0.02 parts by weight of polyvinyl alcohol having a degree of hydration of 72%, and 0.015 parts of polyvinyl alcohol having a degree of hydration of 55%. Parts by weight, 0.035 parts by weight of polyvinyl alcohol having a degree of hydration of 88%, 0.43 parts by weight of polyvinyl alcohol having a degree of hydration of 72%, polyvinyl alcohol with a degree of hydration of 55%, instead of a protective colloid of 0.01 part by weight of hydroxypropylmethyl cellulose. Part by weight, 0.007 parts by weight of hydroxypropylmethyl cellulose protective colloid preparation was added and added when the polymerization conversion range of 30 to 60%, except that 0.015 parts by weight of 88% polyvinyl alcohol was replaced by 0.05 parts by weight. The polymerization was carried out and evaluated under the same conditions as in Example 1.

Example  6

In Example 1, polymerization was performed and evaluated under the same conditions as in Example 1, except that 25 ° C. polymerization water was added instead of 80 ° C. high temperature polymerization water.

Comparative example  One

The polymerization was carried out and evaluated under the same conditions as in Example 1 except that no polyvinyl alcohol was administered at the polymerization conversion rate of 30 to 60% after the polymerization of Example 1 was started.

Comparative example  2

The polymerization was carried out and evaluated under the same conditions as in Example 1 except that the addition time of the polyvinyl alcohol having a degree of hydration of 88% was changed to the polymerization conversion time of 10% to less than 30% after the start of the polymerization.

Comparative example  3

The polymerization was carried out and evaluated under the same conditions as in Example 1 except that the addition time of the polyvinyl alcohol having a degree of hydration of 88% was changed to the time of polymerization conversion of more than 60% after the start of polymerization.

Comparative example  4

Comparative Example 1 except that polyvinyl alcohol having a hydration degree of 55% instead of 88% was continuously administered when the polymerization conversion rate was 30 to 60% after the polymerization was started in Example 1. The polymerization was carried out and evaluated under the same conditions as 1.

Comparative example  5

Comparative Example 1 except that polyvinyl alcohol having a hydration degree of 72% instead of 88% was continuously administered at the time when the polymerization conversion rate was 30 to 60% after the polymerization was started in Example 1. The polymerization was carried out and evaluated under the same conditions as 1.

Comparative example  6

The polymerization was carried out and evaluated under the same conditions as in Example 3, except that no polyvinyl alcohol was administered at the polymerization conversion rate of 30 to 60% after the polymerization of Example 3 was started.

Comparative example  7

The polymerization was carried out under the same conditions as in Example 5, except that 0.05 parts by weight of 88% of the polyvinyl alcohol was added as 0.053 parts by weight as a dispersant to be added in the range of 30 to 60% of the polymerization conversion rate in Example 5. And evaluated.

Comparative example  8

In Example 1, 0.05 parts by weight of 88% polyvinyl alcohol added as protective colloid preparation at the beginning of the reaction was replaced with 0.065 parts by weight, except that no polyvinyl alcohol was added when the polymerization conversion was in the range of 30 to 60%. The polymerization was carried out and evaluated under the same conditions as in Example 1 above.

Comparative example  9

The polymerization was carried out under the same conditions as in Example 3, except that the polyvinyl alcohol having 88% hydration degree and 0.005 parts by weight of the silicone antifoaming agent added when the polymerization conversion rate was in the range of 30 to 60% was used. And evaluated.

The processing properties of the vinyl chloride polymers prepared in Examples 1 to 6 and Comparative Examples 1 to 9 and the polymerization conversion rate during the polymerization reaction were measured by the following methods, and the results are shown in Tables 1 and 2 below.

* Determination of the polymerization conversion rate : Measured using a butane tracer equipped with gas chromatography. When the polymerization conversion curve according to the ratio of vinyl chloride monomer and butane over time under constant polymerization conditions is prepared for each polymerization condition, the polymerization conversion rate according to the polymerization conditions can be measured with high accuracy.

* Measurement of polymerization degree and average particle diameter : measured according to ASTM D1 243-79.

* Apparent specific gravity (BD) measurement : measured according to ASTM D 1895-89.

* Plasticizer Absorption Rate ( wt %) : The amount of DOP absorbed in the sample was expressed in weight% of the sample before absorption in accordance with ASTM D 3367-95.

* Fish eye (fish - eye) can (dog): the vinyl polymer to 100 parts by weight DOP 45 parts by weight of stearic acid, barium, 0.1 part by weight of tin based stabilizer, 0.2 parts by weight of 6-inch roll of carbon black 0.1 parts by weight of 140 ℃ chloride The mixture was kneaded for 4 minutes, and then a sheet having a thickness of 0.3 mm was made and expressed as the number of white transparent particles in 100 cm ² of the sheet.

* Scale generation: In the reactor cleaning step after polymerization, the inside of the reactor and the slurry was dried and sifted after sifting.

(Double-circle): When the scale generation is remarkably improved based on the comparative examples 1 and 6,

(Circle): When scale generation is few based on the comparative examples 1 and 6,

X: When the scale of the same level as the comparative example 1 and 6 generate | occur | produces.

* Particle size distribution measurement : Based on the particle distribution measurement method of ASTM D1 705, the weight percent of the sample that passed through the sieve of # 60 was determined and measured.

Measure
Item unit Example One 2 3 4 5 6 Average particle diameter Μm 179 177 143 178 150 176 Apparent specific gravity g / cc 0.591 0.587 0.552 0.585 0.531 0.590 Plasticizer absorption % 18.2 18.7 26.6 18.9 28.2 18.1 Particle size distribution
(# 60) % 90 89 98 89 97 90 Whether scale occurs - ◎ ◎ ◎ ◎ ◎ ◎ Fusisia dog - - 6 - 6 - Polymerization time minute 195 197 198 197 248 194

Measure
Item unit Comparative example One 2 3 4 5 6 7 8 9 Average particle diameter Μm 175 152 176 171 178 145 148 172 147 Apparent specific gravity g / cc 0.574 0.561 0.573 0.582 0.584 0.545 0.530 0.576 0.551 Plasticizer absorption % 19.3 21.2 19.2 19.1 18.9 27.5 28.3 19.2 26.7 Particle size distribution
(# 60) % 87 88 87 88 89 96 96 87 97 Whether scale occurs - X ○ X ○ ○ X ◎ X ◎ Fusisia dog - - - - - 8 6 - 12 Polymerization time minute 210 201 209 203 202 213 250 211 199

As shown in Table 1, in the case of Example 1 in which the dispersant was continuously added at a conversion rate of 30 to 60% when foaming occurs, and Example 2 intermittently added, Comparative Example 1 was not added additional dispersant The apparent apparent contrast was increased and the particle size distribution was improved. In addition, it was confirmed that scale formation in the reactor was significantly suppressed, thereby improving the efficiency of the reflux condenser, thereby improving productivity through shortening of the polymerization time.

In the case of Comparative Example 2 in which the dispersant was added at a polymerization conversion rate of 10 to less than 30%, it was confirmed that an average particle diameter change occurred compared to Comparative Example 1, thereby affecting physical properties.

In addition, in the case of Comparative Example 3 in which the dispersant was added at the time when the reaction was more than 60%, the scale inhibition and the polymerization time shortening effect did not appear compared to Comparative Example 1.

In Example 4 using polyvinyl alcohol having a degree of 88% hydration and Comparative Example 4 using a 55% degree of hydration polyvinyl alcohol and Comparative Example 5 using a 72% degree of hydration polyvinyl alcohol, the effect of inhibiting scale generation was One was weak.

In addition, in the case of Example 3 in which the ratio of the dispersant was different from that of Example 1 and other polymerization conditions were carried out in the same manner, the generation of scale was suppressed compared to Comparative Example 3, which resulted in shortening of the reaction time and improvement of the quality of the fish oil. The same effect as in Example 1 could be confirmed.

In addition, in the case of Examples 1 to 3 according to the method of the present invention, it was confirmed that the process of the vinyl chloride polymer is the simplest and most advantageous process in terms of improving the apparent specific gravity, improving the particle size distribution, scaling, and suppressing.

On the other hand, Example 4 has a scale inhibitory effect compared to Comparative Example 1, but the apparent specific gravity improvement effect was confirmed to be inferior to Example 1.

Similar results were obtained even when the amount of dispersant 88% hydrated added during the reaction was increased through Example 5 and Comparative Example 7, through which the addition of more dispersant resulted in an increase in manufacturing cost, thereby being added during the reaction. It was found that the content of the 88% hydration dispersant is preferably 0.05 parts by weight or less.

In Example 6 and Example 1 there is no difference, such as the difference in physical properties due to the difference in the temperature of the polymerization water initially input, the temperature difference of the polymerization water is the difference in productivity by giving only the difference in the initial heat-up step (Heat-up) It can be seen that the temperature of the initially introduced polymerization water is high for high productivity.

When the antifoaming agent is added together with the dispersant added during the reaction through Example 3 and Comparative Example 9, it was found that the antifoaming agent is not preferable when the antifoaming agent is added in parallel by increasing the whiskey to increase the functionality of the dispersing agent.

Claims (7)

In the method for producing a vinyl chloride polymer by suspension polymerization,
The suspension polymerization is performed by polymerizing a vinyl chloride monomer, by adding a dispersant.
Method for producing vinyl chloride polymer.
The method of claim 1,
The suspension polymerization is characterized in that the polymerization by the high temperature polymerization water of 70 to 100 ℃ in the reactor
Method for producing vinyl chloride polymer.
The method of claim 1,
The dispersant is characterized in that using polyvinyl alcohol having a degree of hydration of 86 to 92%
Method for producing vinyl chloride polymer.
The method of claim 3,
The addition amount of the polyvinyl alcohol is in the range of 0.005 to 0.050 parts by weight based on 100 parts by weight of the vinyl chloride monomer added before the start of the polymerization.
Method for producing vinyl chloride polymer.
The method of claim 1,
The dispersant may be added continuously or intermittently in a polymerization conversion period of 30 to 60%.
Method for producing vinyl chloride polymer.
The method of claim 1,
The protective colloid preparation is a vinyl alcohol resin having a degree of hydration of 30 to 90% by weight and a viscosity of 4% aqueous solution of 5 to 100 cps at room temperature, 15 to 40% by weight of methoxy group and 3 to 20% by weight of propyl hydroxide group. Using at least one selected from the group consisting of cellulose having a viscosity of 10 to 20,000 cps and unsaturated organic acid measured at room temperature in the range of 0.03 to 5 parts by weight based on 100 parts by weight of the vinyl chloride monomer added before the start of polymerization. Characterized by
Method for producing vinyl chloride polymer.
The method according to claim 6,
The protective colloid preparation includes 0.03 to 0.06 parts by weight of vinyl alcohol resin having a degree of hydration of 85 to 98%, 0.01 to 0.06 parts by weight of vinyl alcohol resin having a degree of hydration of 62 to 82%, and vinyl having a degree of hydration of 50 to 60%. 0.01 to 0.03 parts by weight of alcohol-based resin, and 0.005 to 0.02 parts by weight of cellulose suspension stabilizer, characterized in that
Method for producing vinyl chloride polymer.